How to check wether CType() will throw InvalidCastException?

**Tom Shelton** · Nov 6 '08, 04:45 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

On 2008-11-06, Joe HM <unixverse@yaho o.comwrote:

Hello -
>
I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.
>
I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.
>
Thanks,
Joe

Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If

--
Tom Shelton

**Joe HM** · Nov 6 '08, 05:15 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:

On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:
>

Hello -

>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>

Thanks,
Joe

>
Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If
>
--
Tom Shelton

Hello -

Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.

Thanks,
Joe

**kimiraikkonen** · Nov 6 '08, 06:25 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

On Nov 6, 7:07 pm, Joe HM <unixve...@yaho o.comwrote:

On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:
>
>
>
>
>

On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:

>

Hello -

>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>

Thanks,
Joe

>

Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If

>

--
Tom Shelton

>
Hello -
>
Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.
>
Thanks,
Joe- Hide quoted text -
>
- Show quoted text -

Hi,
As you said and as you have v1.1 (i suppose), you can use a Try-Catch
block and leave Catch block empty. As you know, doing this may be
harmful in future because you won't be noticed if exception fails in
Catch block.

So, in addition to Tom,

'------------------------
Try

Dim o As SomeObject = TryCast(obj, SomeObject)
'Further processing here whether
'casting is successful

Catch
'Leave empty intentionally

End Try
'----------------------

HTH,

Onur Guzel

**kimiraikkonen** · Nov 6 '08, 06:35 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

On Nov 6, 8:21 pm, kimiraikkonen <kimiraikkone.. .@gmail.comwrot e:

On Nov 6, 7:07 pm, Joe HM <unixve...@yaho o.comwrote:
>
>
>
>
>

On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:

>

On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:

>

Hello -

>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>

Thanks,
Joe

>

Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If

>

--
Tom Shelton

>

Hello -

>

Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.

>

Thanks,
Joe- Hide quoted text -

>

- Show quoted text -

>
Hi,
As you said and as you have v1.1 (i suppose), you can use a Try-Catch
block and leave Catch block empty. As you know, doing this may be
harmful in future because you won't be noticed if exception fails in
Catch block.
>
So, in addition to Tom,
>
'------------------------
Try
>
Dim o As SomeObject = TryCast(obj, SomeObject)
'Further processing here whether
'casting is successful
>
Catch
'Leave empty intentionally
>
End Try
'----------------------
>
HTH,
>
Onur Guzel- Hide quoted text -
>
- Show quoted text -

Opps, correcting, of course change TryCast with Ctype or Directcast as
follows:

'------------------------
Try

Dim o As SomeObject = DirectCast(obj, SomeObject)
'Further processing here whether
'casting is successful

Catch
'Leave empty intentionally

End Try
'----------------------

HTH,

Onur Guzel

**Patrice** · Nov 6 '08, 06:45 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

Or you can use TypeOf :

If TypeOf obj Is String Then
etc...

"Joe HM" <unixverse@yaho o.coma écrit dans le message de groupe de
discussion :
11489d66-4a55-4083-86d7-e75c52e7c0be...leg roups.com...

On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:

>On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:
>>

Hello -

>>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>>

Thanks,
Joe

>>
>Dim o As SomeObject = TryCast(obj, SomeObject)
>If Not o Is Nothing Then
>' Do Cool Stuff
>End If
>>
>--
>Tom Shelton

>
Hello -
>
Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.
>
Thanks,
Joe

**Cor Ligthert[MVP]** · Nov 6 '08, 06:45 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

Joe HM

Almost the code as Tom wrote for Net 1.1

\\\
Try
CType(obj, SomeType)
' Do Cool Stuff
Catch
'decide yourself if you want to handle this, I would do it for sure,
while Tom made it just simple as example in my idea.
End Catch
///

Cor

"Joe HM" <unixverse@yaho o.comwrote in message
news:11489d66-4a55-4083-86d7-e75c52e7c0be@1g 2000prd.googleg roups.com...
On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:

On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:
>

Hello -

>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>

Thanks,
Joe

>
Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If
>
--
Tom Shelton

Hello -

Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.

Thanks,
Joe

**Joe HM** · Nov 6 '08, 07:05 PM

Re: How to check wether CType() will throw InvalidCastExce ption?

On Nov 6, 1:40 pm, "Cor Ligthert[MVP]" <Notmyfirstn... @planet.nl>
wrote:

Joe HM
>
Almost the code as Tom wrote for Net 1.1
>
\\\
Try
CType(obj, SomeType)
' Do Cool Stuff
Catch
'decide yourself if you want to handle this, I would do it for sure,
while Tom made it just simple as example in my idea.
End Catch
///
>
Cor
>
"Joe HM" <unixve...@yaho o.comwrote in message
>
news:11489d66-4a55-4083-86d7-e75c52e7c0be@1g 2000prd.googleg roups.com...
On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:
>
>
>
>
>

On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:

>

Hello -

>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>

Thanks,
Joe

>

Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If

>

--
Tom Shelton

>
Hello -
>
Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.
>
Thanks,
Joe- Hide quoted text -
>
- Show quoted text -

Hello -

Thanks a lot for all the feedback. I ended up doing it as follows:
Try
lStringDummy = CType(lObjectDu mmy, String)
Catch lException As System.InvalidC astException
lStringDummy = "CType() FAILED"
End Try

That way I will not intercept any other exceptions.

I was thinking about doing what Patrice suggested (If TypeOf obj Is
String Then ...) but I also want to cast types other than Strings
(e.g. Integers). I guess I could have Or'ed something together but
using the Try/Catch seems to be more flexible.

Thanks again!
Joe

**Cor Ligthert[MVP]** · Nov 7 '08, 11:25 AM

Re: How to check wether CType() will throw InvalidCastExce ption?

Joe,

I was only looking at the solution from Tom.

As ToString is a method of Object, and therefore inherited by every class
that exist. The most easiest way to convert any object to a string is.

Whatever.toStri ng

Cor

"Joe HM" <unixverse@yaho o.comschreef in bericht
news:c316a752-faac-4246-9962-d795e3c59a84@w1 g2000prk.google groups.com...
On Nov 6, 1:40 pm, "Cor Ligthert[MVP]" <Notmyfirstn... @planet.nl>
wrote:

Joe HM
>
Almost the code as Tom wrote for Net 1.1
>
\\\
Try
CType(obj, SomeType)
' Do Cool Stuff
Catch
'decide yourself if you want to handle this, I would do it for sure,
while Tom made it just simple as example in my idea.
End Catch
///
>
Cor
>
"Joe HM" <unixve...@yaho o.comwrote in message
>
news:11489d66-4a55-4083-86d7-e75c52e7c0be@1g 2000prd.googleg roups.com...
On Nov 6, 11:37 am, Tom Shelton <tom_shel...@co mcastXXXXXXX.ne t>
wrote:
>
>
>
>
>

On 2008-11-06, Joe HM <unixve...@yaho o.comwrote:

>

Hello -

>

I was wondering that the "cleanest" way is to determine whether a
CType() will throw an InvalidCastExce ption? I have data I receive as
an Object and I want to convert it to a String whenever possible using
CType(lObjectDu mmy, String) otherwise I will just ignore it.

>

I could put a Try/Catch As System.InvalidC astException around it but I
was wondering if that is the best solution. I once heard that
exceptions should not be used as a tool but rather as a means to
intercept problems during run-time.

>

Thanks,
Joe

>

Dim o As SomeObject = TryCast(obj, SomeObject)
If Not o Is Nothing Then
' Do Cool Stuff
End If

>

--
Tom Shelton

>
Hello -
>
Sorry ... I did not specify that I am using .NET 2003 and I just
checked but there (unfortunately) is no TryCast.
>
Thanks,
Joe- Hide quoted text -
>
- Show quoted text -

Hello -

Thanks a lot for all the feedback. I ended up doing it as follows:
Try
lStringDummy = CType(lObjectDu mmy, String)
Catch lException As System.InvalidC astException
lStringDummy = "CType() FAILED"
End Try

That way I will not intercept any other exceptions.

I was thinking about doing what Patrice suggested (If TypeOf obj Is
String Then ...) but I also want to cast types other than Strings
(e.g. Integers). I guess I could have Or'ed something together but
using the Try/Catch seems to be more flexible.

Thanks again!
Joe

How to check wether CType() will throw InvalidCastException?

How to check wether CType() will throw InvalidCastException?

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